After 200 days of Trumps presidency, his awkward marriage of convenience with Republicans has increasingly come under severe stress

More Republicans will turn against Donald Trump and his politics of populism, a GOP senator and leading critic of the president has predicted, as the Guardian surveys the conservative landscape 200 days into the Trump presidency.

Jeff Flake of Arizona was among 17 conservative politicians, activists, officials and pundits interviewed over two months, revealing that while the president has given rightwing fringe groups a seat at the table, his alliance with his own party remains highly precarious.

I think more of us will say where does this lead, where are we and what happens when we get off this sugar high of populism? said Flake, who believes the Republican party abandoned its core principles and struck a Faustian bargain by embracing Trump in last years election.

What can we do on trade when supply trains get sent around us? Those have long-term ramifications. This is not something that we can flirt with for four years and then quickly snap back, so I do think there needs to be more pushback.

Trump, a former Democrat with no political experience, ran as an anti-establishment candidate effectively staging a hostile takeover of the Republican party. In July 2015 former Texas governor Rick Perry declared: Donald Trumps candidacy is a cancer on conservatism, and it must be clearly diagnosed, excised and discarded. Perry is now Trumps energy secretary.

But after months of criticism that they are too passive, congressional Republicans have flexed their muscles of late over threats from the White House against Robert Mueller, the special counsel investigating Trump and Russia, and Jeff Sessions, the attorney general, and passing fresh sanctions against Moscow that Trump was reluctantly obliged to sign.

In addition, high-profile Republicans at various levels of government have been accused of mounting shadow campaigns for 2020 including Mike Pence, the vice-president, who was forced to issue a statement on Sunday denouncing the New York Times report about his alleged positioning for a post-Trump era as disgraceful and offensive.

Flake, author of a new book, Conscience of a Conservative which argues that conservatism has been compromised by nationalism, populism, xenophobia, extreme partisanship, even celebrity believes that others will join him in breaking ranks.

The talk of firing Jeff Sessions, the AG, is not going over well in the Senate, and Ive been heartened to see so many of my colleagues stand up and say thats not going to happen, because we see it as a precursor to do something else, maybe with the special counsel, and thats not going to happen, said Flake, who believes the Republican party abandoned its core principles and struck a Faustian bargain by embracing Trump in last years election.

So I do think that youre seeing more people stand up and say weve got to respect the institutions. I do think that will continue. I do sense that the Congress is reasserting itself a little more.

Flake acknowledged that Trump has displayed conservative instincts in his cabinet appointments, choice of supreme court justice Neil Gorsuch and plans for regulatory and tax reform. But he said the presidents approach to trade is populist and his temperament unstable. A conservative embraces our allies and recognises our enemies and the kind of chaos that has ensued in both in domestic and foreign policy is very unconservative, he said.

The senators views echo those of other mainstream Republicans who have long resisted Trump. Eliot Cohen, former state department counsellor to George W Bushs secretary of state Condoleezza Rice, added: This fundamentally boils down to character, and his character is rotten. Hes a narcissist who happens to have taken control of the Republican party.

Theres some areas where he agrees with party orthodoxy, and some where he doesnt. But his only doctrine is: whatever is good for Donald Trump is good for the country. When he goes down and he will go down, at some point one of the things that will be striking is just how quickly members of Congress will turn on him.

Trumps awkward marriage of convenience with Republicans has been under severe stress. He alienated members of the House by calling their healthcare bill mean just days after toasting it in the Rose Garden at the White House. He was unable to successfully cajole or persuade members of the Senate to pass their own version and attacked their failure to do so via Twitter, where he often refers to Republicans as they rather than we.

Donald J. Trump (@realDonaldTrump)

Republicans in the Senate will NEVER win if they don’t go to a 51 vote majority NOW. They look like fools and are just wasting time……

But a full divorce would leave the president politically exposed, especially as the investigation into his election campaigns alleged collusion with Russia gathers momentum.

Karl Rove, former senior adviser to George W Bush, said: One of the interesting things is the difficulty of Trump advocating for party loyalty. He is neither a conservative or frankly a longtime Republican. Its one of the reasons why he won. He was able to say, Im against the political system Republican or Democrat I want to blow up Washington. Ive got a giant grenade in my hand. Are you with me?

It does present difficulties in governing. He doesnt have the longtime relationship with people that most candidates for office have.

But Trump has found a more receptive audience among pressure groups in the conservative movement. He retains strong connections with evangelical Christians, anti-tax adherents to the Tea Party, pro-life campaigners and the National Rifle Association in April he became the first sitting president to address its annual convention since Ronald Reagan.

Sean Hannity, a Fox News host, and Tony Perkins, president of the Family Research Council, are among those to enjoy frequent meetings and dinners at the White House. All can bring considerable pressure to bear on the Republican party.

Speaking by phone as he walked down the street, through security and into the White House for a meeting with officials, Grover Norquist, president of Americans for Tax Reform, said of the president: I would argue hes taken a more pro-conservative stand on gun rights, on home schooling, on judges than past Republican presidents. If you want to do a purity test, Reagan and Bush would not have passed on a lot of a things. Trump changes the world on behalf of conservatives.

Trumps ban on transgender troops in the military and a raft of policies on criminal justice, education and immigration have thrown red meat to his allies on the right. Despite numerous setbacks and a sense of chaos in his administration, his approval rating among conservative Republicans is holding steady.

Tom Tancredo, former Congressman for Colorado, put it bluntly: There were two reasons I voted for him: one was he wasnt Hillary Clinton; second was the supreme court. All else is forgiven.

Eliot Cohen, political scientist, former state department counsellor to Condoleezza Rice

This fundamentally boils down to character, and his character is rotten. Hes a narcissist who happens to have taken control of the Republican party. Theres some areas where he agrees with party orthodoxy, and some where he doesnt. But his only doctrine is: whatever is good for Donald Trump is good for the country.

Trump has taken conservatives back to a different era, before William F Buckley drove out the Birchers, the bigots and the antisemites. Were now back in a different world.

When he goes down and he will go down, at some point one of the things that will be striking is just how quickly members of Congress will turn on him.

Rory Cooper, Republican strategist and former aide to former House majority leader Eric Cantor

Trump is undeniably the current leader of a still fractured and damaged Republican party. Some of that damage existed before him and some of it he has and continues to create. But Trump only adheres to conservatism in so much as it protects his 38% base. Even if he lurched to the left now, liberals would never accept him back, so its his only option. But his tendency is still geared toward autocratic rule in the way a mayor of New York City mayor would operate, with a penchant toward pleasing our nations adversaries, some economic protectionism and, most importantly, self preservation.

Its up to Congressional Republicans to protect conservatism, period. President Trump would abandon a conservative position in a minute for just about any selfish reason.

I would argue character and humility is a part of what defines a conservative leader. Reagan was revered for both, and even those disappointed with either Bush hold them in esteem on these two accounts. Trump is severely handicapped in both areas.

If the economy were to run out of steam, which probabilistically seems quite likely, and if theres a foreign policy screw up, then it would be quite easy to see his approval ratings just fall. Populist voters are fickle. Theyve already defected from the Republican establishment; they can defect from him at some point, and its quite non-linear.

I think the Republicans have surprised me in one respect and that was the poor discipline of the party. If you think of this in British terms, essentially we are now in a quasi-monarchy, kind of what Alexander Hamilton vaguely had in mind, but its a monarchy in the sense that the White House is a court and Trump is like one of those people who becomes king whos not terribly well suited to the role, and so theres rampant factionalism and infighting and erratic decisions by the king, and Paul Ryans the prime minister whos trying to manage affairs in the estates general, but the problem is that from a British vantage point the party disciplines very weak. I thought that he would be able to deliver much more cleanly on the healthcare reform and tax reform. It then turned out that actually the partys not a united party at all. All the talk of unified government is belied by the reality.

Jeff Flake, US senator for Arizona and author of Conscience of a Conservative

A conservative embraces our allies and recognises our enemies and the kind of chaos that has ensued in both in domestic and foreign policy is very unconservative.

The Faustian bargain in our case is in the election realising that he was tapping a popular surge and that we could latch on to that and work with him and win short-term battles at the expense of losing the war long-term. Some of these positions that have been taking will have long-term ramifications and Im not sure if we considered that during the election.

Ive been heartened in the last couple of weeks; in the Senate in particular weve more jealously guarded the institution, the Congress. The talk of firing Jeff Sessions, the AG [Attorney General] is not going over well in the Senate and Ive been heartened to see so many of my colleagues stand up and say thats not going to happen, because we see it as a precursor to do something else, maybe with the special counsel [Robert Mueller], and thats not going to happen. So I do think that youre seeing more people stand up and say weve got to respect the institutions. I do think that will continue. I do sense that the Congress is reasserting itself a little more.

I think more of us will say where does this lead, where are we and what happens when we get off this sugar high of populism? What can we do on trade when supply trains get sent around us? Those have long-term ramifications. This is not something that we can flirt with for four years and then quickly snap back, so I do think there needs to be more pushback.

I dont think hes a conservative and I dont think he does either. He wasnt even a Republican until Barack Obama became president.

He was very popular at the Conservative Political Action Conference (CPAC) because his name wasnt Hillary Clinton. Last year Republicans were willing to put up with Trump because of the alternative. But I do know theres grumbling in the hustings. In a while Republicans in the House and Senate will say: This guy says hes a Republican. OK, Gorsuch, got it. What else has done thats positive at all? Theres no strategic vision today on any level or dimension. He uses any action to get his name in the headlines on any given day.

Conservatives have grown used to paddling down the river by themselves. Theyll get back in a few years.

Bill Kristol, commentator and founder of The Weekly Standard

The reason Ive been so anti-Trump is I hate the idea American conservatism becomes Trumpism. I think American conservatism is important to the country. I hate the idea he gets to ruin what I think is a pretty impressive tradition.

Im struck by the way Newt Gingrich has become a ridiculous Trump apologist. Rudy Giuliani was an awfully successful mayor of New York who presided over the revival of a great city; if youre a young person and your exposure to Giuliani has been his defending Trump over the past two years, you think hes an irascible crazy guy.

The problem is Trump. Hes personally such a disreputable figure, he can do a fair amount of damage. The good news is the foreign policy apparatus. His bad impulses have been checked.

In a way conservatism has been vindicated by Trump. Conservatism warns against a demagogue motivated by populism. Its nice we can appeal to conservative writings but we need living conservatives.

Tim Miller, former Jeb Bush spokesman

The thing that surprised me about Trump is that previous iterations of populism within the party, from Buchanan through the Tea party, still held rather strict socially conservative views. What Trump exposed is that these voters werent necessarily looking for a pure truecon but instead they were using those social issues as proxies for their disdain for liberal, urban, elite culture. Trump offered them a candidate who channeled their anger but through anger and mockery of the media and elites, validation of their view that America is not as great as it once was, and a dash of white grievance politics rather than purity.

Trump is not a movement conservative in the philosophical sense so no, he doesnt reflect that in any real way. But he is a reflection of where the conservative base of the party is right now and I think he exposes the wide gap between conservative intellectuals and conservative voters. The question is whether that gap will be bridged by a future candidate or if it will continue to widen and fracture. I dont know the answer to that.

Grover Norquist, president of Americans for Tax Reform

Hes the president. Hes sui generis. Everyone gets that hes sui generis. Theres not a Trump wing of the Republican party. There was a Goldwater wing, there was a Rockefeller wing, theres not a Trump wing. I would argue hes taken a more pro-conservative stand on gun rights, on home schooling, on judges than past Republican presidents. If you want to do a purity test, Reagan and Bush would not have passed on a lot of a things. Trump changes the world on behalf of conservatives.

Were going to get a bundle of critics of Trump. The objection is, He doesnt listen to me and I dont know how to get into the bloodstream of the American agenda if Im not whispering in the ear of the prince. There are people who wish to be consulted as experts on cable TV or New York Times op-eds and they want to be seen as important shapers of the world. The chattering classes didnt like Newt Gingrich either.

Heather Cox Richardson, political historian

I think Trumps a salesman, not a politician. He doesnt adhere to any ideological points except what makes him look good. Its an easy one to blame President Trump but conservatism has its own problems. Ideological conservatism gave up the ghost to movement conservatives because they were winning elections by using racism and sexism. Trump is simply reflecting back what they created.

It increasingly appears that not only Trump but members of Congress have abandoned the American experiment in favour of policies that will favour an oligarchy. Their willingness to work with Putin and Russia negates everything the American experiment is about. I find it simply appalling.

But American women have entered the political sphere in a way they never have before and it will be them who save America. That is the great untold story.

Andy Roth, vice-president, Club for Growth free enterprise group

Aside from an issue or two, hes been very strong on our issues. A very pro-growth president, he has surrounded himself with strong, conservative principled people so if he can focus on the big issues, I think hes going to enjoy a lot of success.

On economic issues, his instincts on our issues have been really really good and it remains to be seen what his impact will be. Its possible a renegotiated Nafta is more free trade than the old version; its possible that he could have glowing marks on all issues.

Karl Rove, former senior adviser to George W Bush

Theres been a bit of populism [in Trumps message], a frequent part of the American political scene, and theres been a certain amount of populism in most successful Republican candidates the part of populism that says Washington or the media look down their nose at flyover America. [But unlike Reagan and George W Bush] this guy is not really a conservative… if you had to attach an ideological label to him, he would be a populist.

One of the interesting things is the difficulty of Trump advocating for party loyalty. He is neither a conservative or frankly a longtime Republican. Its one of the reasons why he won. He was able to say, Im against the political system Republican or Democrat I want to blow up Washington. Ive got a giant grenade in my hand. Are you with me?

It does present difficulties in governing. He doesnt have the longtime relationship with people that most candidates for office have.

Matt Schlapp, chairman of the American Conservative Union

The president ran on an important yet simple agenda and he is executing on that agenda, step by step, day by day. The economy is strong, businesses appreciate the deregulatory environment and the oncoming approach to cut taxes. Donald Trump inherited a lot of dangerous situations around the world so the fundamentals are strong. His people who put him in office are pleased with what hes getting done and not backing down.

The biggest change is you have a president who is upsetting the order of Congress, press, Washington DC and all the usual suspects who are involved in process. Hes taking them all on aggressively which results in a lot of change and a lot of pushback and the nation is divided. As to whether thats a good thing or bad thing, thats the biggest dynamic of the Trump presidency: audacious and aggressive challenge to the status quo and political class, without regard or respect to the position those people hold.

Charlie Sykes, author, broadcaster and columnist

Donald Trump is not a conservative. Hes a man whos entirely without principle or ideology. However, given how many conservatives have embraced him, its becoming difficult to make the case hes not the leader of the conservative movement. CPAC became a festival of Trumpism.

Its disturbing to see the pressure some conservative leaders putting on conservatives to fall into line. It feels like the more the administration melts down, the more intense the pressure to conform.

If you are a conservative there are things he will do that you will applaud, but the price tag is going up all the time. You have to align yourself with a liar and conman because he will make the trains run on time. Accept someone who mocks the disabled and insults women because he gets you a social policy win.

Its not so much what Trump himself does as the effect he has on people around him. Were watching conservativism turn into a cult of personality. The way some conservatives are corrupted by his behaviour has long term implications. Im old enough to remember when character mattered to conservatives. What do they say about character now?

Michael Steele, former chairman of the Republican National Committee

Hes not a conservative. Hes not even a Republican and thats fine. He ran in the Republican primary and Republicans got behind him but actually being moored to the philosophical anchors of the party and policies that the party has supported and advocated for over a generation, no, thats not Donald Trump.

This is my 40th year as a Republican and it is the first time I can honestly say I dont recognise this party and some of the people who are leading it when it comes to those principles and those values that we once purportedly stood for, and we no longer seem to stand for that. I want to know what changed and the only thing thats changed is Donald Trump entered the picture.

With Reagan, George W Bush, George Herbert Walker Bush, even Richard Nixon, there was still a core there that defined what a Republican is, it defined what conservatism is in the context of being a Republican and that now seems to be wholly lost.

Tom Tancredo, former Republican Congressman for Colorado

Hes a populist. He is not averse to using government to solve problems he thinks its capable of solving. I certainly support his efforts for immigration control.

Most conservatives look for certain things hes done and say, good enough for me. The appointment of Neil Gorsuch to the supreme court solidified that in the minds of many. There were two reasons I voted for him: one was he wasnt Hillary Clinton; second was the supreme court. All else is forgiven. There are plenty of times hes said things in his tweets that you wince at but on important points hes doing the right things.

Rick Tyler, political analyst, former Ted Cruz campaign spokesman

Hes not a conservative. I dont think he has any intellectual guideposts or political ideology. He used the tools of populism. Take the infrastructure week: this is low hanging bipartisan fruit but its gone nowhere.

I feel a little alone and isolated as a conservative. My friends are supporting a president and agenda that has nothing to do with conservatism and I find that remarkable. I believe conservatives would do more for the poor, more for the environment.

Bob Vander Plaats, CEO of the Family Leader, social conservative organisation

As I remind our base all the time, Hillary Clinton is not our bar. I know, Trump did this, Trump did that, thank God its not Hillary but Hillary is not our bar. We have the GOP House, we have the GOP Senate; [lets move the] ball down the field.

Frankly, hes still trying to get his sea legs. We believe that there needs to be a higher standard that what [former communications director] Anthony Scaramucci did, not just to Reince Priebus and Steve Bannon, but the way he did it, the words he used. Not only is the world watching, our children are watching, and no entity can fulfill its mission with that dynamic, much less the White House. Even some of the tweets are demeaning. I think right before the election, there was an interview where Trump said, When I get to be president Ill be more presidential than any other president in history; were still waiting for that.